The reliable operation of a portable defibrillator depends critically on the "condition" of its battery. This condition is determined by the available energy that it can deliver to a load, and at what power level this energy can be delivered. With the initiative towards widespread deployment of portable defibrillators, a low-cost device capable of accurately measuring both the State-of-Charge (SOC) and State-of-Health (SOH) of its battery is necessary to ensure that missed defibrillation attempts due to battery failure are eliminated. US Nanocorp and Villanova are collaborating in the pioneering development of an innovative powerful approach, based on fuzzy logic, to battery SOC and SOH determination that is both reliable and cost effective. Traditional measures used to determine battery SOC and SOH such as battery voltage, temperature and impedance form a highly complex, nonlinear relationship with SOC/SOH. The fuzzy logic approach offers a relatively simple method that can model such a relationship with ease. In Phase I, data will be collected in representative batteries (lead acid) used in portable defibrillators, which will be modeled using fuzzy logic to enable accurate soc/soh determination. A prototype SOC/SOH meter will be completed in Phase II. PROPOSED COMMERCIAL APPLICATIONS: Production of battery management equipment is an emerging opportunity in a world wide battery market of $25 B, where growth in portable power devices is increasing at a 20% annual rate. Traditional methods are cumbersome and nongeneric. The proposed fuzzy logic method is very powerful in its efficiency and adaptability to a wide variety of battery chemistries and types.